Apparatus for separating particles according to size



July 31, 1962 H. G. A. DUMONT APPARATUS FOR SEPARATING PARTICLESACCORDING TO SIZE Filed Oct. 14, 1960 uan-0 HUBER? DuMo/vT A 770R A/FYSUnited States Patent "ice This invention relates to particle separationand more particularly to improvements in apparatus for separatingparticles.

In U.S. Patent No. 2,748,941, there is disclosed a screening deviceprovided with a screening deck having the shape of a segment of acylindrically curved surface, feed means having at least one opening fortangentially feeding a liquid and a mixture of particles to be separatedover the full width and onto the concave side of the screening deck,perpendicularly to the generatrices thereof, and means for collectingthe separated fractions. The screening deck is fitted in a holder whichcan turn on a horizontal shaft parallel to the generatrices of thescreening deck so that in one position the one end of -the screeningdeck connects with the feed means, and in the other position the otherend of the screening deck connects with the feed means.

With this device, by periodically interchanging the feed end and thedischarge end of the screening deck, the stream of the material alongthe screening deck can be periodically made to change its direction, asa result of which a uniform wear of the screening deck and a separationat a constant particle size can be insured.

The space required for this device depends on the size of the screeningdeck and the space occupied by the holder and the screening deck duringturning. The dimensions of the screening deck depend on the amount ofmaterial to be treated.

An object of the present invention is the provision of an apparatus ofthe type described which is capable of treating approximately twice theamount of material as the prior art device while at the same timerequiring substantially the same space for reversibility.

Another object of the present invention is the provision of apparatus ofthe type described including a pair of screening decks and meansmounting said screening decks for rotation about a common horizontalaxis between a first operative position wherein the screening decks aresymmetrical about a vertical plane passing through the axis of rotationand one end of each screening deck is arranged to have the suspensionfed thereto at fixed feeding positions and a second position wherein thescreening decks are also symmetrical about the same vertical plane butthe opposite ends thereof are arranged to have the suspension fedthereto at the fixed feeding positions.

These and other objects of the present invention will become moreapparent during the course of the following detailed description andappended claims.

The invention may best be understood with reference to the accompanyingdrawing wherein an illustrative embodiment is shown in a verticalcross-sectional view.

Referring now more particularly to the drawing, the apparatus of thepresent invention includes a frame, generally indicated at 1, which hasa casing, generally indicated at 2, mounted therein. The casing includesa skeletonized structure made up of rigidly interconnected members 3 ofconventional cross-sectional configuration having side plates 4 fixedthereto. A shaft 5 is journalled in the casing and extends between theside plates. Fixed to the shaft outward of one side plate is a handle 6,indicated by dotted lines, by which the shaft can be turned. Disposed inthe casing, symmetrical with respect 3,047,150 Fatented July 31, 1962 toa vertical plane passing through the center of the shaft 5, there aretwo holders 7 and 8 which fixedly receive screening decks 9 and 10,respectively. One of these holders, such as holder 7, is fixed to theshaft 5, by any suitable means such as plates 11, and the other holder 8is rotatably mounted on the shaft 5 by any suitable means such as plates12.

As shown in the drawing, the holders are bounded, at least near the feedand discharge ends of the screening decks, by flat surfaces 13 and, whenthe screening decks are in the operative position, two of these surfacesare inthe vertical plane of symmetry through the center of the shaft 5.The holder 7 is provided, on at least one side, with two pawls 14, eachof which can turn on a shaft 24 and one of which engages, in theoperative position, a pin 15 on the holder 8. The screening decks 9 and10 are kept in place by means of clamping strips 16, wedges 17 and checkrods 18.

At the ends of the screening decks there are oblique plates 19 whichprevent liquid and solid particles to be separated, supplied by afeeding device 20, from falling into the space bounded by the convexparts of the screening decks, and thus getting into a collecting means21 for the underflow fractions from the screening decks. The feedingdevice 20 consists of a funnel-shaped body which is divided into twoequal compartments, as by a wall 22, and into which a feeder mouth-piece23 opens. If necessary, a distribution element 25 may be mounted in thetop of the feeding device. The feeding device has two slot-shapedmouth-pieces 26 and 27, the front and back walls of which are positionedbetween the walls of the holders 7 and 8, and through which liquid andsolid particles are fed tangentially onto the concave sides of thescreening decks.

On either side of the vertical axis of symmetry through the center ofthe shaft 5, the screening device has troughshaped collectingmeans 28for the overflow fractions from the screening decks 9 and 10, each ofwhich is provided with a discharge pipe 29. The collector 21 for theunderflow fractions is funnel-shaped and provided with a discharge pipe30. If necessary, detachable splash plates 31 may cover the bottom partof the casing 2. If desired, the feeding device 20 and the dischargedevices 2-3 may be lined with wear-resistant material. The handle 6 isprovided with a locking device (not shown), through which it can befixed to the casing 2, to prevent the shaft 5 from turning at undesiredmoments.

It can thus be seen that the apparatus of the present invention providesa pair of screening decks 9 and 10 which can be moved by operation ofthe handle 6 and pawls 14 into two operative positions wherein thescreening decks are disposed in symmetrical relation with respect to avertical plane passing through the axis of rotation of the screeningdecks. In a first of the two operative positions, one end of each of thescreening decks is disposed adjacent an associated feed slot to receivethe suspended mixture fed therefrom. In a second operative position, theopposite ends of the screening decks are disposed adjacent the feedslots to receive the suspended mixture fed therefrom. To turn thescreening decks from one operative position to the other, the upper pawl14 is disengaged. This causes the right-hand holder 8 in the drawing torotate on the shaft 5, and the surfaces 13 of the holders 7 and 8 whichwere previously at an angle to each other, to come to rest against eachother. In its new position, the holder 8 is attached by means of thelower pawl 14 to the holder 7. Subsequently, the lock of the handle 6 isdisengaged and the two holders are turned, by turning handle 6, untilthe discharge end A of the screening deck 7 has taken up the position Aand the discharge end B of the screening deck 8 has taken up theposition B the mixture fed thereby.

It thus will be seen that the objects of this invention have been fullyand effectively accomplished. It will be realized, however, that theforegoing specific embodiment has been shown and described only for thepurpose of 'illustrating the principles of this invention and is subjectto extensive change without departure from such principles. Therefore,this invention includes all modifications encompassed within the spiritand scope of the following claims;

I claim:

1. Apparatus for separating particles according to size comprising apair of substantially identical screening decks each having the shape ofa segment of a cylindrically curved surface, feed means for each of saidscreening decks for feeding a mixture of particles and a suspendingliquid at one end over the full width of the associated screening deckonto the concave side thereof in a direction perpendicular to thegeneratrices thereof,

said feed means being fixedly disposed in adjacent parallel relation 'onopposite sides of a vertical plane, and means mounting said screeningdecks for rotational movement about a common'axis disposed in saidverti- V cal plane betweena firstoperative position wherein saidscreening wdecks are disposed in symmetrical relation with respect tosaid vertical plane and one end of each 2. Apparatus as defined in claim1 wherein said screening deck mounting means comprises a holder fixedlyreceiving each of said screening decks, said holders having cooperatingmeans for fixedly securing the same together when said screening decksare disposed in said 4. Apparatus as defined in claim 2 wherein saidholders are provided with flat surfaces extending along opposite endportions of the associated screening decks in planes passing through theaxis of rotation thereof, the

ciated feed means when said screening decks are disposed in either ofsaid operative positions.

6. Apparatus for separating particles according to size comprising aplurality of substantially identical screening decks each having theshape of a segment of a cylindrically curved surface, feed means for atleast two of said plurality of said screening decks for feeding amixture of particles and a suspending liquid at one end over the fullwidth of the associated screening deck onto the concave side thereof ina direction perpendicular to the generatrices thereof, said feed meansbeing fixedly disposed in adjacent relation on opposite sides of avertical plane, and means mounting said plurality of screening decks forrotational movement about a common axis disposed in said vertical planeinto at least two positions in which a different one of said pluralityof screening decks is disposed in each of the following two positions:(1) a first operative position with one end adjacent said feed means toreceive particles and a suspending liquid fed therefrom; and v(2) asecond operative position with the opposite end adjacent said feed meansto receive particles and a suspending liquid fed therefrom.

References Cited in the file of this patent UNITED STATES PATENTS2,748,941 Fontein June 5, 1956 Richardson Oct. 22, 1918

